Field of the Invention
The present invention relates to an image processing apparatus, a method for controlling the image processing apparatus, and a storage medium.
Description of the Related Art
There are two types of copying apparatus including a comparatively small A4 machine which supports a document reading unit for an A4 size and an LTR size and supports sheets of the A4 size and the LTR size and a large A3 machine which supports a document reading unit for a size equal to or smaller than an A3 size including the A4 size and supports sheets equal to or smaller than the A3 size for recording. The A3 machine supports documents in a range from an A5 size to an A3 size and has a reading unit including an automatic document feeder (ADF) having a plurality of document size sensors which detect a document size. When a document is placed on the ADF, states of the document size sensors are changed, and the copying apparatus automatically determines a document size in accordance with the states of the document size sensors and uses the document size in a copy process (refer to Japanese Patent Laid-Open No. 9-297434).
In recent years, there is a demand for printing on sheets of special document sizes only used in specific regions or the like in addition to printing on sheets of document sizes of an A type, a B type, an LTR/LGL type which are generally used.
However, the document size sensors only have accuracy for identifying the representative document sizes, such as the A type, the B type, and the LTR/LGL type. For example, FOLIO, which is an example of a sheet of a special document size, has a document size of 210 mm×330 mm. However, since the document size sensors only have accuracy for identifying the representative document sizes, states of the document size sensors obtained when FOLIO is placed on the ADF correspond to states of the document size sensors obtained when LGL (216 mm×356 mm), which is a representative sheet, is placed on the ADF. In this case, the copying apparatus determines that the document size of the document placed on the ADF corresponds to LGL which is the representative document size in accordance with the states of the document size sensors. In this way, if a document of a special document size which is only used in a specific region or the like is placed on the ADF, the ADF may not appropriately recognize the document size. As a result, the copying apparatus may wrongly determine the document size as another representative document size before determining a reading reference position and a reading length for performing a copy operation. Consequently, a reading range is shifted in printing as a result of the copy.